Question

The rate of $E_1$ reaction depends upon:

• A. the concentration of substrate
• B. the concentration of nucleophile
• C. the concentration of substrate as well as nucleophile
• D. neither the concentration of substrate nor of nucleophile

Answer 1

Answer: (A)

the concentration of substrate

The elimination reaction $E1$ from its name, that $1$ means its unimolecular reaction. $E1$ consists of two consecutive steps:

Step 1: Formation of the carbocation.

Step 2: Attack of the nucleophile.

Since the first step is bond breaking (needs energy) and the second step is bond formation (releases energy), therefore, step 1 is the rate determining step (slow step) and therefore, we have only one reactant which is $R-X$ and the rate, $r=k[R-X]$.